#include<iostream>
#include<unistd.h>
#include<string>
#include<pthread.h>
#include<semaphore.h>

class Sem
{
  private:
    sem_t sem;
  public:
    Sem(int num)
    {
      sem_init(&sem,0,num);
    }
    void P()
    {
      sem_wait(&sem);
    }
    void V()
    {
      sem_post(&sem);
    }
    ~Sem()
    {
      sem_destroy(&sem); 
    }
};

Sem sem(1);
int tickets=2000;

void* GetTickets(void* arg)
{
  sleep(1);
  std::string name=(char*)arg;
  while(true)
  {
    sem.P();
    if(tickets>0)
    {
      usleep(1000);
      std::cout<<name<<" get ticket: "<<tickets--<<std::endl;
      sem.V();
    }
    else 
    {
      break;
    }
  }
  std::cout<<name<<" quit "<<std::endl;
  pthread_exit((void*)0);
}

int main()
{
  pthread_t tid1,tid2,tid3;
  pthread_t tid4,tid5,tid6;
  pthread_create(&tid1,nullptr,GetTickets,(void*)"thread 1");
  pthread_create(&tid2,nullptr,GetTickets,(void*)"thread 2");
  pthread_create(&tid3,nullptr,GetTickets,(void*)"thread 3");
  pthread_create(&tid4,nullptr,GetTickets,(void*)"thread 4");
  pthread_create(&tid5,nullptr,GetTickets,(void*)"thread 5");
  pthread_create(&tid6,nullptr,GetTickets,(void*)"thread 6");
  pthread_join(tid1,nullptr);
  pthread_join(tid2,nullptr);
  pthread_join(tid3,nullptr);
  pthread_join(tid4,nullptr);
  pthread_join(tid5,nullptr);
  pthread_join(tid6,nullptr);

  return 0;
}





